Re: switching from CRT to LCD
The first thing you don't mention is if the lcd screen has a dvi-connector or not. If so I'd recommend you to use this connection in favor of the normal D-SUB (vga-connector). For this you need to add a line "ConnectedMonitor" "DFP".
Further no matter if you use DVI or D-SUB you need to change the refresh rate settings in the monitor section. (I know there's no real refresh rate but the values are still important)